Prior art references have taught the provision of a heat exchanger usable as a grate for a fireplace and including tubing for carrying a fluid to be heated by the heat exchanger. Air can be utilized as the fluid to be heated so that the heated air is distributed through a register to the room in which the fireplace is located or to an adjacent room through suitable ducts. Likewise, water or any other liquid can be utilized with such a heat exchanger to function in a radiator heating system, a convective heating system, or a radiant heating system of either the floor, ceiling, or baseboard type. Fireplace heat exchangers of this type are disclosed by U.S. Pat. Nos. 495,418; 547,802; 670,066; 1,252,176; 1,426,976; 1,549,071; 2,172,711; 4,025,043; 4,046,320; and 4,074,676. Other fireplace heat exchangers are disclosed by U.S. Pat. Nos. 712,672 and 3,394,697.
Enclosed stoves which are normally designed to burn wood or coal function much more efficiently than fireplaces since the supply of oxygen to the burning fire can be limited and the distribution of the heat to the room radiates in all directions from the stove body. However, as with fireplaces, some heat is lost through the flue to the environment.